Dengue fever is caused by a mosquito-borne RNA virus. One hundred million cases of dengue fever occur annually worldwide, making dengue virus the most significant arbovirus in terms of global morbidity. Dengue fever can present clinically with symptoms similar to other febrile illnesses that are not transmitted by mosquitoes, such as measles. The ability to rapidly differentiate between dengue and other flavivirus infections (or unrelated diseases) could expedite vector control measures, and would provide a basis for appropriate patient management. In Phase I research, we will produce and evaluate a novel recombinant dengue antigen in a micrtoiter plate immunoassay for detecting virus-specific IgG and IgM. The sensitivity and specificity of the recombinant antigen-based assay will be compared to conventional whole virus antigen preparations using paired acute and convalescent sera from primary and secondary infections of the four dengue serotypes and Japanese encephalitis. The ability of the recombinant antigen to form complexes with anti-dengue antibodies will also be evaluated in a nitrocellulose membrane/latex-particle sandwich immunoassay, in order to illustrate that the selected reagents and conjugates are functional in a format analogous to the semi-quantitative dipstick test to be developed and validate during Phase II. PROPOSED COMMERCIAL APPLICATION: The potential market for a dengue rapid-immunodiagnostic product includes the 100 million people infected worldwide with dengue virus each year. The proposed rapid test could penetrate this poorly exploited market and supplant the cumbersome, time-consuming techniques historically used for dengue serodiagnosis.